1. Field of Invention
This invention relates to concrete slab-on-grade fabrication, and more particularly, to systems and methods for forming insulated concrete foundations.
2. Description of Relevant Art
Combining formwork with insulation improves building thermal performance by providing a concrete foundation with insulation, and speeds installation by eliminating the need to strip concrete forms after slab pour. Among the benefits of utilizing “leave-in-place” insulation forms are reduced heating season energy consumption (and associated emissions reductions) and reduced jobsite waste because disposable wood form boards are not being used.
A conventional method uses a “leave-in-place” insulation form that comprises a rigid plastic outer piece filled with foam insulation. This system requires a separate footing pour to provide a rigid anchor for the outer forms, which increases both material and labor costs. This system does not provide a continuous termite barrier to protect the building framing from termite infestation.
Integrated concrete forms, or ICFs, have recently gained widespread use. Integrated concrete forms usually consist of hollow blocks made of expanded polystyrene reinforced with metal or plastic straps. They are used to build foundation walls and even above-grade structure walls. However, the use of ICFs on standard slab-on-grade foundations common to many tract homes is limited, because ICFs require level footings and also that the two sides of the ICFs be tied together.
Conventional slab-edge insulation practice is to frame a slab foundation using wood form boards (or other materials), pour the foundation, and then remove and dispose of the forms. The slab-edge insulation for the foundation is then secured to the slab in an entirely subsequent operation. Thus, conventional slab-edge insulation practice requires three distinct processes and often three different visits to the home site to perform each of the three processes, respectively.
What is needed are systems and methods for forming insulated concrete foundations that eliminate two of those processes. What is needed is a cost effective system to integrally form and insulate concrete slab foundations while providing pest resistance and the ability to work with post tension slab techniques that have become commonplace in many areas of the country. What is needed are leave-in-place slab-edge insulated forms that are robust, simple to install, and utilize corner and linear joining pieces that facilitate installation.
The above factors suggest a need and opportunity for improved systems and methods for forming insulated concrete foundations that reduce costs and enhance installation reliability.